Ω♠∆{kokukai}∆♠Ω

(modern era)

Kokushibo was a bodyguard for a businessman named Muzan. Muzan had asked Kokushibo to kidnap a boy who owed him money. Kokushibo agreed. Muzan told Kokushibo that the boy's name was Kaigaku, that he studied at the Kimetsu Academy. Kokushibo went, saw Kaigaku, knocked him out, and put him in a luxurious black car.

When Kaigaku woke up, his wrists were bound with a chain attached to a wooden bed rail. Kaigaku tried to break the chain but couldn't. He heard someone open the door; it was Kokushibo. Kokushibo took off his gloves and looked seriously at Kaigaku. What are you trying to do?

Kokushibo is of legal age and Kaigaku is of legal age